This invention relates in general to the method of providing an inflatable underwater structure about one or more steel structural members which can be used to create a sub-sea artificial environment around a work area to easily and safely permit such work activities as inspection, welding, x-raying and painting.
A very serious problem which has been facing the off-shore oil industry is the great difficulties involved in properly maintaining and repairing the sub-sea steel structural support members in off-shore platforms and in the various submarine pipeline systems. A particularly acute problem has been in trying to weld in a sub-sea environment.
In attempting to overcome these problems the prior art has tried to use steel diving and welding chambers in order to create an artificial environment or atmosphere for sub-sea work. However, such chambers are inordinantly expensive and clumsy to use. Moreover, when the work has to be done in an area where there are several steel structural members radiating out at different angles, the diving chambers could not be used or else, if used, often caused more damage to the associated production tubes or risers or to the secondary structural members than originally existed on the member to be repaired.
Alternately, welding techniques have been devised for welding directly in the wet environment but these techniques have been unsatisfactory and highly dangerous and usually produced a high percentage of inferior weldments.
The present invention overcomes the problems of the prior art by providing an inflatable underwater structure which can be used regardless of the structural complexity of the work area to create an artificial, gaseous environment such as air around the sub-sea work area. As will be seen more fully below, the inflatable structure is relatively inexpensive, takes no esoteric skills to assemble, other than certain basic training, and allows for the ideal environment within which the work may be performed. Thus, with air in the inflatable structure a worker need not use the relatively clumsy scuba diving equipment while he is at work.
The inflatable structure can be broken down as desired for easy portability and because of its relative inexpensiveness can be stocked at many locations in the field to allow for immediate use.
These and other great advantages and objects of the present invention over the prior art will become apparent in the description and discussion of the details of the preferred embodiments presented below.